Method and apparatus for removing organic layers

ABSTRACT

Embodiments in accordance with the present invention provide methods and apparatuses for heating a substrate with radiation during processing of substrates. Radiation in the radio or microwave portion of the electromagnetic spectrum is applied to a substrate housed within a processing chamber to promote desirable chemical reactions involving the substrate. Processing in accordance with embodiments of the present invention may utilize pressurization of the processing chamber in conjunction with the application of microwave, RF, IR, or UV radiation, or electromagnetic induction, to heat the substrate or a component of the processing chemistry present within the chamber. Alternative embodiments of the present invention may use combinations of these energy types for more effective processing. For example, UV radiation may be introduced into the chamber in conjunction with microwave heating in order to generate reactive species from the processing chemistry.

CROSS-REFERENCES TO RELATED APPLICATIONS

[0001] This nonprovisional application claims priority from provisionalapplication No. 60/387,155, filed Jun. 6, 2002 and hereby incorporatedby reference for all purposes. This nonprovisional application alsoclaims priority as a continuation-in-part of U.S. parent applicationSer. No. 10/150,748, filed May 17, 2002, also hereby incorporated byreference for all purposes.

BACKGROUND OF THE INVENTION

[0002] During fabrication of semiconductor devices, it is frequentlyuseful to develop an organic photoresist material in a pattern thatserves as a mask for processes such as etching or ion-implantation.Following ion-implantation of metals into a masked substrate, however,the developed organic photoresist mask is difficult to remove withoutdamaging the underlying material.

[0003] Conventionally, such ion-implanted organometallic photoresistmaterials are removed in two stages. First, the substrate bearing theorgano-metallic material is exposed to an oxygen asher using amicrowave-induced plasma. This initial ashing step typically results insubstantial amounts of particles/implanted metals remaining on thesurface of the substrate.

[0004] Therefore, a second step of exposing the ashed substrate surfaceto wet processing in the piranha process with Caro's acid (a combinationof sulfuric acid and hydrogen peroxide) at temperatures over 100° C. isconventionally employed. Neither of the ozone ashing nor the wetprocessing stages are effective alone. Moreover, the intense microwaveradiation applied to generate the plasma creates long-lived reactivechemical species, typically radicals, which may damage fragilestructures present on the substrate surface.

[0005] Accordingly, there is a need in the art for improved methods andapparatuses for treating a semiconductor wafer.

BRIEF SUMMARY OF THE INVENTION

[0006] Embodiments in accordance with the present invention providemethods and apparatuses for heating a substrate with radiation duringchemical processing. Specifically, radiation in the radio or microwaveportion of the electromagnetic spectrum is applied to a substrate housedwithin a processing chamber in order to promote desirable chemicalreactions involving the substrate. Processing in accordance withembodiments of the present invention may utilize the application ofmicrowaves, RF, IR, or UV radiation, or electromagnetic induction, toheat the substrate. Alternative embodiments of the present invention mayuse combinations of these energy types for more effective processing.For example, UV radiation may be introduced into the chamber inconjunction with microwave heating in order to generate reactive speciesfrom the processing chemistry.

[0007] Processing in accordance with embodiments of the presentinvention may take place at elevated pressures to enhance concentrationsof reactant material, or may take place at sub-ambient pressures inorder to prolong the lifetime and hence processing effectiveness ofradicals or other reactive species present within the chamber. Oneparticular promising embodiment of the present invention is thestripping of photoresists that have been subjected to ion implantation,utilizing exposure of the implanted wafers to ozone gas.

[0008] Processing chemistry introduced into the chamber to react withthe heated substrate may be in the form of a gas, a liquid, or somecombination of a gas and a liquid such as a mist. Alternatively, theprocessing chemistry could also be utilized in the form of a solid suchas a dust. In these cases, the processing chemistry may be transportedto or through the processing chamber under the influence of a pressuredifferential.

[0009] An embodiment of a method in accordance with the presentinvention for performing processing of a substrate, comprises, providinga processing chamber, inserting a substrate into the processing chamber,and introducing a processing chemistry into the processing chamber. Theprocessing chamber is pressurized by at least one of introducing acomponent of the processing chemistry into the processing chamber andintroducing a gas into the processing chamber. Radiation is applied toheat at least one of a layer of the substrate and a component of theprocessing chemistry, thereby promoting reaction between the substrateand the processing chemistry, wherein the pressurizing step occurs atleast one of before, after, and simultaneously with radiationapplication step.

[0010] An embodiment of an apparatus in accordance with the presentinvention for processing a substrate, comprises, a chamber in fluidcommunication with a processing chemistry source, and a pressurizationsource in fluid communication with the chamber, the pressurizationsource operable to increase a pressure within the chamber duringprocessing. A radiation source is in communication with the chamber toheat at least one of a layer of a substrate, a substrate contactingmember, and a processing chemistry positioned within the chamber.

[0011] A further understanding of the nature and advantages of theinventions disclosed herein may be realized by reference to theremaining portions of the specification and the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 shows a simplified cross-sectional view of one embodimentof an apparatus for processing a substrate in accordance with thepresent invention.

[0013]FIG. 2 shows a simplified cross-sectional view of an alternativeembodiment of an apparatus for performing processing in accordance withthe present invention.

[0014]FIG. 3 shows a simplified plan view of another alternativeembodiment of a processing apparatus in accordance with the presentinvention.

[0015]FIG. 4 shows a simplified cross-sectional view of anotheralternative embodiment in accordance with the present invention.

[0016]FIG. 5 shows a simplified plan view of yet another alternativeembodiment of a processing apparatus in accordance with the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

[0017]FIG. 1 shows a simplified cross-sectional view of one embodimentof an apparatus 10 for processing a substrate in accordance with thepresent invention. Substrate or wafer 2 is supported upon turntable 4positioned within chamber 6. Substrate 2 may comprise a number ofdifferent materials, including but not limited to silicon, GaAs, andother semiconductor materials, quartz, borosilicate glass, flat paneldisplays, microelectro-mechanical (MEMS) devices, hard disk substrates,biomedical slides, and other media. The surface of substrate 2 mayfurther comprise patterned layers of different materials such asdielectric, metallic, organic, or organo-metallic materials. For thepurposes of this application, the term “organo-metallic” refers to anycarbon-containing material which also includes one or more metals. Oneexample of an organometallic material is organic photoresist materialthat has been ion-implanted with metals such as phosphorous or boron.Another example of an organometallic material are the chemicalby-products of plasma etching, which may deposit on the sidewalls ofdevice features.

[0018] Chamber 6 includes inlet 8 and outlet 9 for receiving andexhausting respectively, chemistries intended to react with substrate 2.Chamber 6 may be completely or partially closed, such that theprocessing chemistries may be maintained under elevated or reducedpressures during processing. Chemistries introduced into chamber 6 forprocessing may comprise any gas, liquid, or gas/liquid combinationintended to react with substrate 2 or material present thereon.

[0019] Chamber 6 is composed of material permeable to radiation utilizedin heating the substrate or a layer of material on top of the substrate,such that radiation 12 emitted by generator 14 enters chamber 6,contacts wafer 2, and results in heating of wafer 2 or a layer on wafer2. Alternatively, chamber 6 may comprise material that is not permeableto the radiation, but may further include a window comprising aradiation-permeable material which permits entry of the radiation intothe chamber.

[0020] Radiation generator 14 may comprise a magnetron 11 incommunication with the chamber through a waveguide 13. Radiationgenerator 14 may comprise a generator of microwave radiation offrequency 915 or 2450 MHz. Such microwave sources typically exhibit apower of between about 300 and 1200 W. However, a microwave generatorutilized by embodiments in accordance with the present invention is notlimited to any particular frequency or power range, and alternativelycould be of a specialized industrial design utilizing a specific fixedor changeable power, frequency, or pulse duration. For example,generators utilizing variable frequency, variable power, and/orprecisely controlled power levels could also be advantageously utilizedin accordance with embodiments of the present invention.

[0021] Waveguide 13 is configured to receive radiation from generator14, and to convey this radiation in a single mode to chamber 6. Chamber6 is designed to ensure that the applied radiation uniformly heats thesubstrate(s) located therein. In one embodiment, chamber 6 may exhibitdimensions sufficiently similar to waveguide 13 to preserve the unipolarcharacter of the applied radiation. While not wishing to be limited toany particular approach, in one possible embodiment of the presentinvention utilizing unipolar radiation, interior surfaces of the chambercould be lined with radiation-absorbing materials to suppress internalreflectance of the radiation giving rise to unwanted multi-moderadiation.

[0022] It may also be desired that radiation applied to the chamber toheat the wafer will be multi-mode radiation. This is because manymaterials, including single crystal silicon substrates utilized in thefabrication of semiconductor devices, are relatively transparent tomicrowave radiation, with a majority of the energy of the radiationencountering the substrate will pass through without being absorbed.Accordingly, the methods and apparatuses in accordance with embodimentsof the present invention may require the passage of reflected radiationin order to effect the desired rapid heating.

[0023] Application of multi-mode radiation to the processing chamber toaccomplish uniform heating of substrates positioned therein can beaccomplished in several ways. In the specific embodiment illustrated inFIG. 1, uniform heating of the wafer(s) is ensured by rotating thewafers utilizing a turntable, relative to the direction of the appliedradiation. Alternatively, a mode stirrer structure such as a rotatingmetal fan could be positioned in the chamber such that unipolarradiation incident from the generator is reflected at random within thecavity to heat substrate(s) present therein. Further alternatively, themicrowave generator could emit radiation of oscillating frequencies ordiffering pulse durations in order to accomplish uniform heating withmulti-mode radiation in accordance with embodiments of the presentinvention. Still further alternatively, multiple microwave generatorscould be employed to simultaneously apply radiation having a pluralityof modes.

[0024] The embodiment of FIG. 1 shows wafer 2 supported horizontally onturntable 4 in a plane parallel with the direction of radiation 12 fromgenerator 14. However, the present invention is not limited to thisparticular configuration, and in an alternative embodiment the substratecould be supported perpendicular relative to the incident radiation, orin any other orientation relative to the direction of radiation emittedby the generator.

[0025] In operation, substrate 2 is positioned upon turntable 4 withinchamber 6. A processing chemistry is flowed into chamber 6 through inlet8. Radiation 12 from generator 14 is transmitted into chamber 6 and intocontact with wafer 6, resulting in heating of wafer 2. Radiation 12 mayalso indirectly contact wafer 2 by reflecting off of the interiorsurfaces 6 a of the chamber 6.

[0026] As a result of interaction between the radiation 12 and wafer 2or a layer of material present thereon, the wafer or the materialoverlying the wafer is heated. Chemistry present in chamber 6 thenreacts with heated substrate 2 or materials present on the surfacethereof. The elevated temperature of the substrate, combined with thereactive properties of the processing chemistry, effectuate a desiredchemical reaction.

[0027] At the conclusion of processing, or during processing where acontinuous flow of processing chemistry is passed through the chamber,the spent processing chemistry may be evacuated from chamber 6 throughoutlet 9. Radiation generator 14 ceases applying radiation to chamber 6,allowing the processed wafer 2 to cool at a much faster rate than isexperienced with conventional contact heaters. The rapid coolingafforded by embodiments in accordance with the present invention allowsfor faster throughput and hence reduced operating costs

[0028] Embodiments in accordance with the present invention are notlimited to performing any particular type of chemical processing on asubstrate. One particularly promising application for the presentinvention is in the stripping (removal) of patterns of organometallicphotoresist material from the surface of a semiconductor wafer utilizingozone. In such an embodiment, the elevated temperature of themicrowave-heated substrate promotes rapid reaction with the ozone toconsume the organometallic material.

[0029] In accordance with an embodiment of the present invention, theapplication of microwave radiation may be decoupled from application ofa reactive ozone-containing oxygen gas, or other processing chemistry.In an implanted-photoresist stripping process, the implanted wafer isheated and an independent generator creates ozone from oxygen. The ozonegas does not interact with the microwave energy and hence is notaffected by the microwave energy and does not decompose until reachingthe heated surface of the organo-metallic coating. The ozone produceddoes not include large quantities of high energy reactive ions orradicals which can damage sensitive structures present on the wafersurface.

[0030] Due to the high concentration of relatively low energy reactivespecies at the substrate surface resulting from the decomposition ofozone, substrates cleaned utilizing this process in accordance with thepresent invention may be substantially free of residues. In oneexperiment, a positive novolac photoresist resin having a thickness of12,500 Å was formed on each of two 200 mm wafers. The photoresist on thefirst wafer was implanted with arsenic, and the photoresist on thesecond wafer was implanted with phosphorous. Both the As and P implantswere performed at a dose of about 3×10¹⁵ atoms/cm² with an implantenergy of 50 KeV at 10,000 μA.

[0031] The wafers bearing the implanted resist were then heated atatmospheric pressure in a 1100 W microwave oven operated at a powersetting of 40%, while ozone gas generated at a concentration of greaterthan about 150,000 ppm was forced through the oven chamber at a flowrate of 1.5 slm. As a result of this processing, the wafers werestripped clean of the implanted photoresist in less than eight minutes.For purposes of comparison with conventional photoresist removalprocesses, the same implanted resist material was not stripped at allutilizing conventional high or low temperature ozone processes.

[0032] While the above experiment describes removal of photoresistmaterial through exposure to gas generated with an ozone concentrationof about 150,000 ppm, this is not required by the present invention andother ozone concentrations could be utilized, ranging from 1000 to400,000 ppm and greater, as there is no known upper limit in theconcentration of ozone useful in accordance with the present invention.In addition, while the above experiment involves the application ofozone as an oxidant, this is not required by the present invention andother oxidizing species or combinations of oxidizing species, such asoxygen, hydrogen peroxide, and other peroxides, could alternatively beutilized.

[0033] In the photoresist stripping or other applications utilizingembodiments in accordance with the present invention, the processingchemistry may be maintained under positive pressure within either asealed or substantially sealed processing chamber to enhance theeffectiveness and/or rate of the process. Discussion of processing atelevated pressures is described in detail in copending parent U.S.patent application Ser. No. 10/150748, filed May 17, 2002 andincorporated by reference herein for all purposes.

[0034] As described in detail in the above-incorporated application,processing under positive pressures may be accomplished by flowingprocessing fluids into a sealed processing vessel, or by flowingprocessing fluids into a processing vessel having a outlets of limitedcapacity such that pressure within the processing vessel increases abovethe pressure at the exit or exhaust from the outlet from the vessel. Forgaseous or compressible processing chemistries and components, thisincreased pressure within the processing vessel may result in anincrease in volumetric concentration. Elevated pressures within thechamber during processing would most typically lie between about 1 and100 ATM. In accordance with certain embodiments of the present inventionthe processing vessel can be pre-pressurized.

[0035] Increased pressure and/or elevated concentration of activeprocessing components in the gas phase may promote direct interactionbetween the gas phase component and the wafer surface. Alternatively orin conjunction with direct interaction between the gas phase componentand the wafer surface, increased gas phase pressure may enhance theresulting concentration of these components in a liquid phase that maybe present in the chamber, thereby increasing desirable processingeffects such as chemical reactivity. Such pressurized processing,performed at elevated temperatures resulting from the application ofradiation in accordance with embodiments of the present invention, mayeven further enhance the rate and effectiveness of such processing.

[0036] While processing in accordance with embodiments of the presentinvention may be characterized as being performed in a “chamber”, adiscrete processing vessel is not required where as processing fluid isflowed to or through a processing region by virtue of a pressure drop.And while embodiments in accordance with the present invention justdiscussed may operate at greater than atmospheric pressure, otherembodiments may operate at less than atmospheric pressure, for examplewhere the processing chamber has been evacuated prior to theintroduction of processing chemistry.

[0037] Combinations of chemistries may be introduced into the chamber inaccordance with embodiments of the present invention. For example, acidsmay be employed in conjunction with the oxidant to enhance the processof photoresist removal. Examples of acids which may be utilized ascomponents of processing chemistries in accordance with embodiments ofthe present invention include, but are not limited to, inorganic acidsand organic acids such as acetic acid, formic acid, butyric acid,propionic acid, citric acid, oxalic acid, and sulfonic acid. Such acidscould be introduced into the chamber in the gaseous phase, in the liquidphase in the form of droplets, or in the solid phase in the form ofdust. Other examples of active components of process chemistries includebut are not limited to surfactants and chelating agents.

[0038] While the present invention has been described above inconjunction with heating a semiconductor wafer to promote removal of anorganometallic photoresist utilizing an ozone-based chemistry, thepresent invention is not limited to this particular application. Methodsand apparatuses in accordance with the present invention could beemployed in conjunction with other types of processing chemistries toperform other types of wafer processing. Examples of other types ofwafer processing suited for the present invention include, but are notlimited to etching inorganic layers such as silicon oxide or siliconnitride overlying a substrate, and performing a post-processing cleaningsuch as those analogous to the RCA cleaning series as is well-known inthe art.

[0039] In addition, while the above description focuses upon applicationof microwave radiation to heat the contents of the chamber, this is notrequired by the present invention. Forms of radiation other thanmicrowave could be applied to heat substrates present within thechamber, and the methods and apparatuses would fall within the scope ofthe present invention. For example, alternative embodiments inaccordance with the present invention could employ electromagneticinduction heating (EMIH) of substrates utilizing radiation ranging infrequencies of a few MHz to tens of GHz.

[0040] Moreover, FIG. 1 illustrates only one embodiment of an apparatusfor performing processing in accordance with the present invention, andother apparatuses and methods would also fall within the scope of thepresent invention. For example, FIG. 2 shows a simplifiedcross-sectional view of an alternative embodiment of an apparatus forperforming processing in accordance with the present invention.Apparatus 20 of FIG. 2 is similar to that shown in FIG. 1, but furtherincludes a water-filled coil 22 within chamber 24. Water-within coil 22absorbs radiation within the chamber and heats up, thereby dampening theeffect of radiation reflected off of the walls of the chamber.

[0041] While the embodiment of FIG. 2 includes a coil filled with acirculating water stream to absorb radiation within the chamber, thepresent invention is not limited to this configuration. Other approachesinclude coating the chamber walls with a radiation-absorbing material,spraying a mist of water or other radiation-absorbing material in thechamber or onto the surface of the wafer, or simply placing a tank ofwater or other radiation-absorbing material within the chamber.

[0042]FIG. 3 shows a simplified plan view of another alternativeembodiment of a processing apparatus in accordance with the presentinvention. Apparatus 30 of FIG. 3 is similar to that shown in FIG. 1,but turntable 32 is configured to support and rotate a plurality ofwafers 34 relative to the direction of radiation 36 emitted frommicrowave generator 38. In addition, inlet 40 and outlet 42 of chamber44 are configured such that a continuous supply of processing chemistryis flowed across surfaces 34 a of wafers 34. Again, while the embodimentof FIG. 3 shows substrates 34 oriented perpendicular to the direction ofmicrowave radiation 36, this is not required by the present invention.Substrates 34 could be supported by turntable 32 in other orientationsrelative to the microwave generator 38. In addition, while FIG. 3 showsrotation of a turntable structure supporting the wafer, this is also notrequired by the present invention. In alternative embodiments, thesubstrates could be rotated relative to radiation within the chamberthrough contact between a rotating or spinning roller or otherstructure, and an edge of the substrate.

[0043]FIG. 4 shows a simplified cross-sectional view of anotheralternative embodiment of a processing apparatus in accordance with thepresent invention. Apparatus 40 of FIG. 4 is similar to that shown inFIG. 1, but additionally includes source 42 of ultraviolet (UV)radiation in communication with chamber 44 through the chamber walls orthrough a UV-permeable window in the chamber walls. While UV radiationsource 42 is located outside chamber 44 in FIG. 3, this is not requiredby the present invention and in alternative embodiments the UV radiationsource could be present directly within the chamber.

[0044] UV source 42 provides to chamber 44 radiation 46 having asubstantially shorter wavelength range (10⁻⁶≦λ≦10⁻⁸ m) than themicrowave radiation (10⁻⁴≦λ≦10⁻¹ m) provided by microwave source 48.Accordingly, UV radiation 46 transmitted to the chamber 44 may allowadvantageous interaction with chemistries present within the chamber.

[0045] For example, applied UV radiation having a wavelength of 254 nmmay generate highly reactive species such as molecular oxygen or oxygenradicals from ozone within the chamber. Alternatively or in conjunctionwith this process, applied UV radiation having a wavelength of 222 nmcould generate hydroxyl radicals from hydrogen peroxide present withinthe chamber. In accordance with still another alternative embodiment ofthe present invention, UV radiation at 172 nm may be applied from asource such as an excimer lamp to oxygen present within a processingchamber. This 172 nm UV radiation can result in formation of reactiveoxygen radicals directly from molecular oxygen, without the need forozone at all. Other potentially reactive species generated from theapplication of UV radiation includes but is not limited to N₂O, whichupon irradiation may form the highly reactive oxygen radical.

[0046] In any of these approaches, the proximity of the radiation sourceto the surface of the substrate results in close proximity of thegenerated radical species to the surface with which reaction is desired.Rapid reaction with the substrate surface can thus occur before theshort-lived radical species generated by interaction with the UVradiation decay into non-energized species and reduce the effectivenessof the processing.

[0047] Moreover, introduction of the gaseous species into an evacuatedchamber may prolong the lifetime of radicals and other reactive speciesgenerated by interaction with the UV radiation. Accordingly, theembodiment of an apparatus shown in FIG. 4 includes a vacuum pump 50 influid communication with the chamber, allowing for evacuation of thechamber during processing. Utilization of low-pressures is not limitedto UV-assisted processing in accordance with the present invention,however, and low pressures could be employed without UV radiation.

[0048]FIG. 5 shows a simplified plan view of yet another alternativeembodiment of a processing apparatus in accordance with the presentinvention. Apparatus 50 of FIG. 5 is similar to that shown in FIG. 4,but microwave source 52 and UV source 54 are positioned on oppositesides of wafer 56, with microwave source 52 proximate to wafer backside56 a and UV source 54 proximate to wafer front side 56 b. The embodimentshown in FIG. 5 allows a flow of inlet gas to be provided across boththe wafer front side and back side, with exhaust port 58 utilized bothto maintain a continuous flow of processing chemistry across the surfaceof the substrate, and to remove spent processing chemistry.

[0049] In certain applications, the embodiment shown of FIG. 5 couldexploit the presence of wafer 56 or materials in intimate contacttherewith or present thereon, to absorb the incident microwave or rfradiation and become hot, while at the same time the wafer package mayblock and/or reflect the microwave or radio frequency radiation andprevent it from reaching and interacting with processing chemistriesoverlying the front side of the wafer. The configuration shown in FIG. 5allows UV radiation to be applied simultaneous with microwave waferheating to achieve the processing desired. While the embodiment of FIG.5 shows the UV source in direct communication with the chamber, this isnot required by the present invention and the UV radiation could bedirected to the chamber and wafer through a reflecting/focusing networkcomprising lenses or mirrors.

[0050] Embodiments of methods and apparatuses in accordance with thepresent invention offer a number of advantages over conventionalprocessing techniques. One advantage is enhanced precision of heatingand a corresponding increase in processing effectiveness. For example,it may be desirable to employ ozone in the chamber to accomplishprocessing such as stripping of photoresist material. However, thestability of ozone declines with increased temperature. Conventionalprocessing approaches utilizing contact heating of wafers or heating ofwafers through exposure to hot gases may result in heating of the entirechamber rather than just the wafer itself. In such conventional contactheating approaches, ozone or other reactive processing chemistry maydecompose prior to reaching the surface of the wafer. This decompositionreduces the effectiveness and rate of processing.

[0051] By contrast, embodiments in accordance with the present inventionapply microwaves to the chamber to accomplish specific, precise heatingof the wafer without resulting in generalized heating of the entirechamber. Ozone or other reactive processing chemistries introduced intothe chamber will thus remain intact until they reach the hot surface ofthe wafer, whereupon the desired processing reaction can efficientlytake place.

[0052] Another advantage offered by embodiments in accordance with thepresent invention is increased throughput. Specifically, the transfer ofthermal energy to and from the wafer during heating and cooling consumestime, and can reduce the effective throughput of an apparatus.Conventional approaches for heating a wafer may employ contact heating,requiring both the contacting member and the wafer to be heated to anelevated temperature. Moreover, such conventional approaches maytypically employ cooling of both the heated wafer and the heatingmember, through mechanisms such as convection utilizing a flow of acooling gas or a cooled structure within the chamber. However, thisapproach wastes much of the energy utilized in heating, which must beremoved from the processing chamber during each run.

[0053] By contrast, many embodiments in accordance with the presentinvention avoid the use of a separate contacting member, such that thereis no need to heat and then cool the contacting member in addition tothe wafer. The application of microwave radiation to heat the wafer, andthe cessation of application of microwave radiation to allow cooling ofthe wafer, occur without any delay time associated with heating orcooling of a proximate contact member. The increased speed andefficiency of heating and cooling increases throughput of the processingchamber.

[0054] Still another advantage offered by embodiments in accordance withthe present invention is enhanced exposure of surfaces of the substrateto processing chemistries. For example, conventional contact heatingtechniques typically employ a heated member in direct physical contactwith, or in close physical proximity to, at least one surface of thesubstrate, typically the wafer backside. The presence of this contactingmember can physically interfere with the flow of processing chemistriesto the wafer backside surface, thereby reducing processing effectivenessand flexibility, particularly as wafer backside cleanliness emerges asan important issue in semiconductor fabrication.

[0055] Heating of the wafer in accordance with embodiments of thepresent invention, however, avoids this drawback. The substrate can besupported in the chamber by its sides or edges, with application ofmicrowave or other radiation serving to heat both the wafer front sideand the wafer backside. Processing chemistries can then be appliedsimultaneously and flow unimpeded to the heated front side and backsideof the wafer to accomplish the desired chemical reaction.

[0056] A further advantage of embodiments in accordance with the presentinvention is the ability to conduct rapid thermal processing. Inconventional apparatuses and methods utilizing contact heating of thewafer, the application of thermal energy to the wafer is prolonged bythe time required to heat up and cool down the contacting member. Thisextended time of exposure to high temperatures must be accounted for inthe thermal budget allowed for a particular process in order to avoidunwanted effects such as migration of implanted dopants within asubstrate.

[0057] In accordance with embodiments of the present invention however,heating and cooling of the wafer is extremely rapid due to the absenceof an intervening contacting member. The ability to rapidly andprecisely apply thermal energy to the substrate increases the precisionof the processing in a manner analogous to rapid thermal processing(RTP) techniques known in the art, and may prevent unwanted phenomenasuch as thermally-induced dopant migration. Embodiments in accordancewith the present invention would be expected to heat an exposedsubstrate or process chemistry at a rate of between about 10° C. and10,000° C./min. Similarly, by the selected application of coolingtechniques to the processed wafer, a heated substrate or processchemistry could be cooled at a rate of between about 10° C. and 10,000°C./min.

[0058] Yet another advantage offered by embodiments in accordance withthe present invention is the ability to selectively heat differentcomponents of a processing chemistry present within the chamber. Forexample, microwave or other radiation may tend to heat one component ofa processing chemistry while leaving other components relativelyunaffected. For example, certain polar compounds (such as water orhydrogen peroxide) may be relatively lossy or easily absorb the appliedradiation and heat up quickly, while other compounds (such astetraethoxysilicate-TEOS) are relatively transparent or inert inresponse to exposure to the applied radiation.

[0059] Therefore, in accordance with embodiments of the presentinvention, it may be possible to tailor the processing to accomplish aparticular goal. One component of the processing chemistry couldadvantageously be heated through exposure to the radiation, while thetemperature of another component of the processing chemistry remainsrelatively constant. This difference in temperature between thecomponents of the processing chemistry can advantageously impartenhanced activity and/or selectivity to a particular cleaning orstripping process. An example of this effect could be present in aapplication utilizing ozone with a water mist, where the water is heatedby the radiation but the ozone is relatively unaffected.

[0060] A still further advantage of embodiments in accordance with thepresent invention is increased flexibility. In conventional contactheating systems, the substrate is cooled by convection as a coolingairflow containing processing chemistry is flowed past the substrate. Insuch conventional approaches, the mass transfer of processing chemistryto the wafer surface is limited by the need to maintain the wafer abovea certain temperature. Embodiments in accordance with the presentinvention, however, decouple the mass transfer of processing chemistryto the wafer surface from the cooling effects, such that the power ofthe radiation can be increased to compensate for cooling effectsassociated with an elevated flow of processing chemistry.

[0061] Embodiments in accordance with the present invention aregenerally applicable to any processing step wherein it is desired toapply thermal energy to a substrate. Thus while the invention has beendescribed above in connection with stripping developed organicphotoresist material through exposure to ozone, the invention is notlimited to this particular application. An example of another processingstep which may be performed in accordance with the present invention isetching inorganic material through exposure to an acid, for exampleremoval of silicon dioxide through exposure to HF in a gas or dissolvedin a liquid solution. A nonexclusive list of acids which may be employedto etch inorganic layers in accordance with embodiments of the presentinvention include F₂, Cl₂, HF, HCl, H₂SO₄, H₂CO₃, HNO₃, H₃PO₄, AquaRegia, chromic and sulfuric acid mixtures, sulfuric and ammoniumpersulfate mixtures, and various combinations thereof.

[0062] In still other applications for embodiments of the presentinvention, the processing chemistry introduced into the chamber maycomprise a base. A non-exclusive list of bases which could be utilizedby embodiments in accordance with the present invention includes but isnot limited to NH₃, NH₄OH, NaOH, TMAH, and KOH. These materials can bein the form of a gas, liquid, or solid.

[0063] In still further applications for embodiments of the presentinvention, the processing chemistry introduced into the chamber maycomprise a surfactant. In accordance with still other applications forembodiments of the present invention, the processing chemistryintroduced into the chamber may comprise a chelating agent such asethylenediaminetetracetic acid (EDTA).

[0064] Wafer cleaning is yet another type of processing which may beperformed in accordance with the present invention. In wafer cleaningapplications, unwanted residue from prior processing remaining on awafer surface is removed in preparation for further processing. Suchwafer cleaning may involve exposing the wafer to a single cleaningchemistry, or may involve exposing the wafer to a series ofcomplementary cleaning chemistries.

[0065] General classes of chemistries useful for wafer cleaning includeacidic solutions, basic solutions, aqueous solutions containingoxidizing components, and combinations thereof. One class of reactantthat may be useful for substrate cleaning or other processingapplications in accordance with the present invention are organic acids.A list of such organic acids includes, but is not limited to, aceticacid, formic acid, butyric acid, propionic acid, citric acid, oxalicacid, and sulfonic acid.

[0066] One example of a particular wafer cleaning process is the RCAwashing series generally known in the art. This multi-step wetprocessing employs a series of five complementary chemical baths toremove the residual organic materials, particles and metals. In a firststep, the substrate is subjected to a heated aqueous bath of H₂SO₄ andH₂O₂ to form Caro's acid (H₂SO₅) to remove residual organic materials,for example developed photoresist material remaining on a substratesurface. In a second step, the substrate is subjected to a diluteaqueous HF bath at room temperature to remove the oxide layer andimpurities contained therein. In a third step, the substrate issubjected to a heated aqueous bath of ammonium hydroxide (NH₄OH) andH₂O₂, to remove particles and other contaminants. In a fourth step, thesubstrate is subjected to a heated aqueous bath of hydrochloric acid(HCl) and H₂O₂, to remove metals. Finally, in the fifth step, thesubstrate is again subjected to a bath of dilute hydrofluoric acid (HF)to remove the oxide layer formed by oxidation in the prior step, freeingmetallic contaminants embedded in the oxide layer and permitting theirremoval, and rendering the surface of the wafer hydrophobic. Inaccordance with embodiments of the present invention, radiation may beapplied during one or more of the above-referenced RCA cleaning steps toenhance their effectiveness.

[0067] Wafer surface modification is still another type of processingwhich may be advantageously performed in accordance with embodiments ofthe present invention. For example, a processing chemistry comprisingelevated concentrations of a reducing agent such as hydrogen gas may bepresent in a chamber to passivate or alter surface properties of asubstrate, or to conduct a process wherein reaction with the processingchemistry present within the chamber leads to a reduced surfacestructure. Thus during processing of a silicon wafer, hydrogen gas oranother reducing agent may be present to minimize formation of an oxidelayer, or to replace hydrophilic surface SiO bonds with hydrophobic SiHbonds.

[0068] While the present invention has described heating of a waferutilizing microwave radiation, it is not required that the temperatureremain constant during processing. Embodiments in accordance with thepresent invention could utilize heating according to predeterminedtemperature gradients in order to achieve maximum effectiveness. Inaddition to temperature, other processing parameters could also bevaried over time. For example, the timing of introduction of variouscomponents of the processing chemistry could be specifically tailored toaccomplish certain results. Moreover, where the processing chemistry ispresent under pressure, this pressure could vary over time to effectuateprocessing in accordance with embodiments of the present invention.

[0069] While embodiments in accordance with the present invention mayrelate to chemical processing of substrates utilized during themanufacture of semiconductor devices, for example substrates comprisingsilicon, SiGe, GaAs, Si, GaAs, GaInP, and GaN to name a few. However,the present invention is not limited to processing of semiconductorsubstrates, and other materials may be subjected to microwave heatingduring processing. Examples of other candidates for chemical processingutilizing the present invention include, but are not limited to, harddisks and hard disk substrates, optical devices such as mirrors, lenses,or waveguides, and substrates utilized in the fabrication ofmicro-electrical mechanical systems (MEMS), liquid crystal displaydevices, biomedical slides, optical devices, mirrors, lenses,waveguides, substrates for DNA or genetic markers, liquid crystaldisplays, and other media. In particular embodiments, these substratescould be intentionally coated with a radiation-absorbing material inorder to enhance their temperature-responsiveness under exposure toapplied radiation. The use of multiple layers of different types ofradiation-absorbing materials to tailor temperature responsiveness isalso contemplated in accordance with embodiments of the presentinvention.

[0070] Although the invention has been described in terms of preferredmethods and structures, it will be understood to those skilled in theart that many modifications and alterations may be made to the disclosedembodiments without departing from the invention. Hence, thesemodifications and alterations are intended to be considered as withinthe spirit and scope of the invention as defined by the appended claims.For example, while some examples of specific embodiments previouslydescribed may suggest a particular sequence of steps, these particularsequences are not required by the present invention.

What is claimed is:
 1. A method for performing processing of a substratecomprising: providing a processing chamber; inserting a substrate intothe processing chamber; introducing a processing chemistry into theprocessing chamber; pressurizing the processing chamber by at least oneof introducing a component of the processing chemistry into theprocessing chamber and introducing a gas into the processing chamber;and applying radiation to heat at least one of a layer of the substrateand a component of the processing chemistry, thereby promoting reactionbetween the substrate and the processing chemistry, wherein thepressurizing step occurs at least one of before, after, andsimultaneously with radiation application step.
 2. The method of claim 1wherein the applied radiation comprises at least one of microwave, UV,IR, RF and electromagnetic induction.
 3. The method of claim 1 furthercomprising applying ultraviolet radiation into the chamber to generate areactive species from the processing chemistry.
 4. The method of claim 3further comprising evacuating the processing chamber prior topressurizing the processing chamber to a level greater than anevacuation pressure in order to prolong the lifetime of the reactivespecies generated from the processing chemistry.
 5. The method of claim3 wherein: a wavelength of the ultra-violet radiation comprises one of254 nm, 222 nm, 172 nm; and the processing chemistry comprises one ofozone, hydrogen peroxide, oxygen and N₂O.
 6. The method of claim 1wherein microwave radiation is applied to the chamber to heat at leastone of one layer of the substrate, the substrate-contacting member, anda component of the processing chemistry.
 7. The method of claim 6wherein the microwave radiation is applied to the chamber in a singlemode configuration.
 8. The method of claim 6 wherein the microwaveradiation is applied to the chamber in a multi-mode configuration. 9.The method of claim 6 wherein at least part of the chamber walls arecoated with a microwave absorbing material to reduce reflections withinthe chamber.
 10. The method of claim 1 wherein at least one layer of thesubstrate is heated by electromagnetic inductive heating.
 11. The methodof claim 1 wherein the radiation source emits radiation varying in atleast one of frequency, power, wave form, and pulse duration.
 12. Themethod of claim 1 wherein a temperature in the processing chamberchanges during processing.
 13. The method of claim 1 wherein at leastone component of the chemistry changes concentration during processing.14. The method of claim 1 wherein the processing chemistry comprises atleast one of a gas, a liquid, a droplet, a mist, a vapor, and a solid.15. The method of claim 1 wherein at least part of the substrate surfaceis contacted with the processing chemistry.
 16. The method of claim 1wherein the substrate comprises at least one layer.
 17. The method ofclaim 1 wherein the substrate moves relative to at least one of thechamber and the processing chemistry during at least part of theprocessing.
 18. The method of claim 1 wherein the radiation is directedtowards the substrate at least one of parallel, perpendicular and at anangle between parallel and perpendicular.
 19. The method of claim 1wherein the processing chemistry comprises at least one of an acid, abase, an oxidant, a reducing agent, deionized (DI) water, and an organicsolvent.
 20. The method of claim 19 wherein the acid comprises aninorganic acid.
 21. The method of claim 19 wherein the acid comprises anorganic acid.
 22. The method of claim 21 wherein the organic acid isselected from the group consisting of acetic acid, formic acid, butyricacid, propionic acid, citric acid, oxalic acid, and sulfonic acid. 23.The method of claim 19 wherein the oxidant is selected from the groupconsisting of ozone, oxygen, a peroxide, and oxide of nitrogen.
 24. Themethod of claim 19 wherein the base is selected from the groupconsisting of NH₃, NH₄OH, NaOH, TMAH, and KOH.
 25. The method of claim19 wherein the organic solvent is selected from the group consisting ofNMP, photresist stripper, semi-aqueous stripper, and methylene chloride.26. The method of 19 wherein the reducing agent comprises hydrogen. 27.The method of claim 1 wherein the processing chemistry comprises ozonein a concentration range of between about 100 and 400,000 ppm.
 28. Themethod of claim 1 wherein the processing chemistry contacts both sidesof the substrate simultaneously.
 29. The method of claim 1 wherein atleast one component of the processing chemistry is selectively heated bythe radiation.
 30. The method of claim 1 wherein the processingchemistry comprises at least one of the list of the standard RCAchemistries including H₂SO₄, H₂O₂, H₂SO₅, HF, NH₄OH, and HCl.
 31. Themethod of claim 1 wherein the processing chemistry comprises one of asurfactant and a chelating agent.
 32. The method of claim 1 wherein afirst processing chemistry contacts one side of the substrate and then asecond processing chemistry contacts another side of the substrate. 33.The method of claim 1 wherein the radiation is directed towards a backside of the substrate.
 34. The method of claim 1 wherein the radiationis directed toward a front side of the substrate.
 35. The method ofclaim 1 wherein multiple processing chemistries are used.
 36. The methodof claim 1 wherein the processing of a substrate comprises multipleprocessing steps performed in at least one of the same and differentprocessing chambers.
 37. The method of claim 1 wherein the substrate isselected from the group consisting of silicon, GaAs, SiGe, Si, GaAs,GaInP, and GaN quartz, borosilicate glass, a flat panel display, asubstrate bearing microelectro-mechanical (MEMS) devices, a hard disksubstrate, a biomedical slide, a substrate for DNA and genetic markers,an optical device, a mirror, a lens, a waveguide, and a liquid crystaldisplay (LCD).
 38. The method of claim 1 wherein the substrate comprisesa patterned layer of a dielectric, metallic, organic, or organo-metallicmaterial.
 39. The method of claim 1 wherein the processing comprises atleast one of removing material from a substrate, adding material to asubstrate, and modifying a substrate.
 40. The method of claim 1 whereinthe radiation is directed to the chamber and wafer through areflecting/focusing network comprising lenses and mirrors.
 41. Themethod of claim 1 wherein the processing chemistry comprises at leastone of F₂, Cl₂, HF, HCl, H₂SO₄, H₂CO₃, HNO₃, H₃PO₄, Aqua Regia, chromicand sulfuric acid mixtures, sulfuric and ammonium persulfate mixtures,and various combinations thereof.
 42. The method of claim 1 wherein thesubstrate comprises at least one layer of radiation absorbing material.43. The method of claim 1 wherein during application of radiation thesubstrate is in contact with a member comprising a radiation-absorbingmaterial.
 44. The method of claim 1 wherein the substrate comprises atleast one silicon wafer.
 45. The method of claim 1 wherein the substrateheats up at a rate of between 10 and 10,000° C./min.
 46. The method ofclaim 1 further comprising cooling the heated substrate at a rate ofbetween 10 and 10,000° C./min.
 47. The method of claim 1 whereinpressurizing the process chamber results in a pressure greater thanatmospheric pressure.
 48. The method of claim 47 wherein pressurizingresults in a pressure of between about one and 100 ATM during theprocessing.
 49. The method of claim 48 wherein pressurizing results in apressure of between about one and 10 ATM during the processing.
 50. Themethod of claim 1 wherein the pressurizing the process chamber resultsin a pressure of less than or equal to atmospheric pressure.
 51. Themethod of claim 1 further comprising evacuating the processing chamberprior to pressurizing the processing chamber to a level greater than anevacuation pressure.
 52. An apparatus for processing a substrate, theapparatus comprising: a chamber in fluid communication with a processingchemistry source; a pressurization source in fluid communication withthe chamber, the pressurization source operable to increase a pressurewithin the chamber during processing; and a radiation source incommunication with the chamber to heat at least one of a layer of asubstrate, a substrate contacting member, and a processing chemistrypositioned within the chamber.
 53. The apparatus of claim 52 wherein theradiation source comprises a source of at least one of microwave, UV,IR, RF, and electromagnetic induction radiation.
 54. The apparatus ofclaim 52 further comprising a substrate support positioned within thechamber and configured to support a substrate such that an orientationof the substrate changes relative to the radiation source duringprocessing.
 55. The apparatus of claim 52 further comprising a substratesupport positioned within the chamber, the substrate support comprisingat least one layer of radiation absorbing material.
 56. The apparatus ofclaim 52 further comprising a vacuum pump in fluid communication with aprocessing chamber to allow evacuation at least one of prior to andafter the pressurization.
 57. The apparatus of claim 52 furthercomprising a mode stirrer positioned in the chamber and configured todeflect radiation from the radiation source during processing.
 58. Theapparatus of claim 52 wherein the radiation source is configured to emitradiation varying in at least one of frequency and power.
 59. Theapparatus of claim 52 wherein the radiation source is in communicationwith the chamber through a radiation permeable window.
 60. The apparatusof claim 52 wherein the radiation source is in communication with thechamber through a network comprising at least one of lenses and mirrors.61. The apparatus of claim 52 further comprising a second radiationsource.